Link Following

Affecting git package, versions <2.22.5-r0

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NVD Description

Note: Versions mentioned in the description apply to the upstream git package. See Remediation section below for Alpine:3.10 relevant versions.

Git is an open-source distributed revision control system. In affected versions of Git a specially crafted repository that contains symbolic links as well as files using a clean/smudge filter such as Git LFS, may cause just-checked out script to be executed while cloning onto a case-insensitive file system such as NTFS, HFS+ or APFS (i.e. the default file systems on Windows and macOS). Note that clean/smudge filters have to be configured for that. Git for Windows configures Git LFS by default, and is therefore vulnerable. The problem has been patched in the versions published on Tuesday, March 9th, 2021. As a workaound, if symbolic link support is disabled in Git (e.g. via git config --global core.symlinks false), the described attack won't work. Likewise, if no clean/smudge filters such as Git LFS are configured globally (i.e. before cloning), the attack is foiled. As always, it is best to avoid cloning repositories from untrusted sources. The earliest impacted version is 2.14.2. The fix versions are: 2.30.1, 2.29.3, 2.28.1, 2.27.1, 2.26.3, 2.25.5, 2.24.4, 2.23.4, 2.22.5, 2.21.4, 2.20.5, 2.19.6, 2.18.5, 2.17.62.17.6.

Remediation

Upgrade Alpine:3.10 git to version 2.22.5-r0 or higher.

References

CVSS Score

7.5
high severity
  • Attack Vector
    Network
  • Attack Complexity
    High
  • Privileges Required
    None
  • User Interaction
    Required
  • Scope
    Unchanged
  • Confidentiality
    High
  • Integrity
    High
  • Availability
    High
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CVE
CVE-2021-21300
CWE
CWE-59
Snyk ID
SNYK-ALPINE310-GIT-1083872
Disclosed
09 Mar, 2021
Published
10 Mar, 2021